No abstract

There are multiple neurotransmitters and neuromodulator systems mediating memory formation among which the endocannabinoid system plays a critical role in the memory formation by modulating the release of many neurotransmitters. Nucleus accumbens appears to have a site in the central of neuronal circuits of the limbic system and to be responsible for the integration and consolidation of inputs from other parts of the brain. In this study the influence of bilateral intra-nucleus accumbens shell microinjections of cannabinoid receptor agents on memory consolidation in adult male rats using passive avoidance task was investigated. The results showed that the intra-accumbens shell microinjection of ACPA as a CB1 receptor agonist (6 ng/rat) immediately after training decreased passive avoidance memory consolidation, while administration of its antagonist (AM251) at different doses did not affect passive avoidance memory consolidation. However, co-administration of AM251 (60 ng/rat) with an effective dose of ACPA prevented the impairment memory consolidation induced by ACPA. These results suggest that the accumbens shell cannabinoid system as a modulating system is involved in aversive memory consolidation including passive avoidance memory.

Background and Aim: Epilepsy is a common brain disorder. Brain function can be affected by the intestinal microflora. The intestinal microflora have a major role in modulating immune responses, producing essential metabolites and mediating neurotransmitters. Antibiotics can affect and reduce these roles and functions by eliminating the intestinal microflora. The aim of this study was to investigate the effect of intestinal natural micro flora removal on seizure susceptibility and seizure behavior modification with the use of probiotics in male Wistar rats. Methods & Materials: This study was performed on 32 male Wistar rats with weight range 200-250 gr. The animals were randomly divided into four groups: 1. Control group; 2. Antibiotic group; 3. Probiotic group and 4. Antibiotic + probiotic group. To remove the microflora, antibiotics (neomycin, ampicillin, and metronidazole) for three weeks and for replacement of microflora, probiotics (Lactobacilli casei, Lactobacillus acidophilus and Bifidobacterium bifidum) for four weeks were administered. Seizures were performed by intraperitoneal injection of pentylentrazole. The microflora was examined by the MRS Agar medium and the Pure Plate method. The data were statistically analyzed in Graph Pad Prism V. 8. Ethical Considerations: This study was approved by the Research Ethics Committee of Arak University of Medical Sciences (Code: IR.ARAKMU.REC.1395.176). Results: The use of antibiotics lead to decrease the number of intestinal bacteria (P<0.0001), increased the severity and stability of seizure stages (P<0.05) and decreased the time delay of seizure onset (P<0.05) compared to the control group. Probiotic consumption by modifying the intestinal microflora (P<0.0001) reduced the severity of seizure and increased the time delay of seizure onset (P<0.05). Conclusion: Elimination of microflora has the potential to induce seizures, which can be compensated by administration of probiotics.